The Research About The UV-VUV Photoluminescence Of Several Typically Orthorhombic Rare-earth Oxides With Different Structure Activated By Dy~3+ Ion

In different materials, the luminescence property of one activator ion is different, that depend on material’s crystal structure. In the seven crystal system, the four space lattices can only occur in orthorhombic system at the same time. Therefore the orthorhombic oxides should be studied systemically as a type of host material, because they can have abundantly different crystal structures. The lanthanon have been applied to the luminescence region, because they have plentiful energy levels and can be excited by different energy. In these lanthanon, Dy3+ ion presents two dominating emissions, which are all from the level of 4F9/2, namely,4F9/2→6H15/2 (470 nm～500 nm) and 4F9/2→6H13/2 (570 nm～600 nm), the latter emission attributes to super-sensitive transition, and its△J=2. The emission of Dy3+ ion is always close to white light, but it appreciably nears yellow region when super-sensitive transition is dominant. Through adjusting the ratio of the two emission peaks, Dy3+ ion can emit white light directly, thus it’s suitable for application on illumination materials. This paper studies the luminescence properties of the orthorhombic oxides with different crystal structures activated by Dy3+ ion. On the one hand the vacuum ultraviolet (VUV) luminescence characters of these oxides have been studied for application on mercury-free lamp, and on the other hand the ultraviolet (UV) luminescence properties of above oxides also have been detailedly studied for applying to LEDs. At the same time, the luminescence properties of the same activator Dy3+ ion in the different crystal structural oxides have been detailedly studied and they have compared by different aspects, such as diffuse reflection spectra, the calculation of host electron structure and the mechanism of energy transfer. Therefore through combining above experimental dates with theory, the relationship between luminescence properties and crystal structure could be concluded and evaluated.The study about the luminescence properties in UV-VUV regions of the typically orthorhombic materials with different crystal structure activated by Dy3+ ion, including SrB4O7:Dy3+,Zn2+, KSrPO4:xDy3+,yLi+(0≤x≤5%,0≤y≤1.5), KZnPO4:xDy3+ (0≤x≤3%), Zn1-x-yDyxAlyNb2O6 (2%≤x≤13%,2%≤y≤13%), CaIn2O4:xDy3+,yM (M=Zn2+,Gd3+,Al3+) (0.2%≤x≤1%), (0≤y≤0.6%) presents:(1) SrB4O7:Dy3+ present excellent luminescent property under VUV excitation, and with variation of doping amount of Dy3+, its color coordinates can be adjusted expediently; under 365 nm excitation, the luminescence intensity of SrB4O7:Dy3+ can be enhanced by doping with Zn2+ ions, because the absorption band of Zn-O is near 365 nm, and its color coordinates can be adjusted expediently by adjusting concentration of Zn2+ ions; is a specific matrix which can reduce Eu3+ ions to Eu2+ in air, in this paper, energy from sightless emission Eu+ ions can be transferred to red emission Eu3+ ions, furtherly, it can enhance the luminescence efficiency of Eu3+ ion and realized energy transfer between three ions firstly. (2) Through studying the luminescence property of ABPO4:Dy3+ (A=K+;B=Sr2+,Zn2+), KSrPO4:Dy3+ is considered as a excellent luminescence material for VUV application, the best one present white light with a little yellow, and its color coordinates is (0.364,0.395); under UV excitation the luminescenc intensity of KSrPO4:Dy can be enhanced by chargy compensation of Li+ ions, the best one KSrPO4:3%Dy3+,1.3%Li+ present white light with a little yellow, and its color coordinates is (0.377,0.418). Through different wavelength exciting KZnPO4:Dy3+, the luminescence of vacancy of Zn2+ and interstitial Zn+ can be observed in its emission spectra. (3) In ZnNb2O6:Dy3+, energy can be transferred from CTS to characteristic excitation peaks of Dy3+ through Al3+ ions, its can improve the deficiency of characteristic excitation peaks of Dy3+. (4) In CaIn2O4:xDy3+, through doping with Zn2+,Gd3+和Al3+ ions, the luminescence instensity can be enhanced and the color coordinates also can be changed. (5) Through studying about the luminescence properties of BaZr(BO3)2:Eu3+, we furtherly understanded that when rare-earth ions enter into the different sites of crystal lattices, different erengy excitation can affect the luminescence properties, and thereby we can deelply understand the difference luminescence properties of exciting different sites’s ions. Besides above, we can furtherly research on its luminescence properties through the calculation about the electronic structure of BaZr(BO3)2 for validating our experimental results.